This invention concern an apparatus for manufacturing air-cushion dispatch packages.
Air-cushion dispatch packages are becoming increasingly popular for the mail order dispatch of products sensitive to pressure or susceptible to shocks, due to their cushioning effect and because of their relatively low weight. An apparatus for manufacturing them mechanically is alreay known which comprises two unwinding mechanism for coated sodium paper with the traction of the paper webs regulated by friction brakes. The unwinding mechanism also comprises a single web of air-cushion foil which is formed from a folded triangle to a semi-tupe and guided between the paper webs. This apparatus also comprises means for hot-sealing and subsequent cooling the paper webs with the web of air-cushion foil introduced therebetween, in the region of the edge of the dispatch package. Separate longitudinal and transverse sealing rails and corresponding cooling rails are provided. The paper webs with the sealed-in air-cushion foil are conveyed by means of a traction mechanism and the dispatch packages are cut to the desired format in longitudinal cutting means and transverse cutting means.
A disadvantage of the known apparatus in practical operation is that a relatively large amount of waste is produced during the manufacture of air-cushion dispatch packages. Among other things this is caused by tension arising during the sealing of the paper webs with the web of air-cushion foil and the resulting lateral divergence of the paper webs provided with the sealed-in web of air-cushion foil and the necessity of having to stop the machine to change the rolls of air-cushion foil. A further drawback is that it is not only relatively awkward but also time-consuming to change the format of the dispatch package to be manufactured. The known apparatus also causes traction marks on the dispatch qackage in the form of undesirable indentations with the danger that the air-cushion can become damaged. A still further drawback is that the sealing rails may be soiled and stuck from sealing which may cause the dispatch packages to become soiled as well. The manufacturing process has to be interrupted regularly to clean the sealing rails and this leads to production losses.
Specific apparatus for producing air-cushion mailing bags are referred to in DE-OS 2,629,679. This known apparatus comprises a paper unwinding means for a single paper web and an air-cushion sheet unwinding means for a single air-cushion sheet web, the air-cushion sheet web secured to the paper web by means of edge transverse sealing being folded over in a folding station to form a semihose.
A disadvantage with this known apparatus is that with it only a single mailing envelope or bag can be made in one working cycle and said bag does not have a relatively firm edge zone as lateral protection against impacts on all sides. Furthermore, in the known apparatus a relatively large number of rejects occur due to the occurrence of stresses in the sealing of the paper web to the air-cushion sheet web and the subsequent folding. Another disadvantage is that a format change in the mailing bag to be manufactured is relatively complicated and time-consuming.
DE-OS 2,164,152 refers to a protection container and a method for production thereof in the form of a mailing bag in which a lateral edge sealing is disclosed. However, due to the folding operation, production of mailing bags with a stable edge protection region all round is not possible.
U.S. Pat. No. 3,896,712 refers to an apparatus for the automatic production of envelopes which have a simple format adjustment by rotatable pinions which engage into a system with racks and spindles. There is no reference to the specific production of air-cushion mailing bags or envelopes and the problemes they involve.
At least some of the above-mentioned problems are to be solved by the invention.